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UDS venting questions

post #1 of 18
Thread Starter 

Well I had my maiden voyage cook on my UDS yesterday...I wanted to do something simple just in case the UDS didn't perform.


Anyway...built exactly to specs as the UDS on the Pickled Pig forum...I put in 1/2 a fire basket of lump Royal Oak charcoal (green bag)  and then started my charcoal starter chimney with 12 briquettes of Royal oaks charcoal (red bag)..and then 5 pieces of cherry wood on top of all that in my fire basket.


I hav 24 chicken legs season with jerk sauce on the grate.  I got the smoker up to 230F..and capped the 2 lower vents that use pipe caps..and then my ball valve that runs up the side of my barrel, so I don't have to bend over..I left all the way open...temps dropped down to 215F....and so I uncapped one vent..and closed the ball valve half way and she heated up to 270F....


It seems that I can't get the happy medium with my vent setup.  It either cools down too much or heats up too much.


Any thoughts?????



post #2 of 18

You will want to practice a bit more so you get the idea on how you drum will run but for the most part they are all very similar in my experience. First of all like we always ask is your thermometer accurate? Where are you placing your thermometer in the smoker? I have a analog thermometer mounted on the smoker then I always put my wireless thermometer in there as well so I have two or three reference points for heat while I am smoking. One thing you are going to notice when you are first starting up your barrel the heat can be different depending on where you are measuring your temps in the smoker. For example my analog one may say 180 on the outside of the barrel and my digital one may say 215 at the center of the barrel. Once the fire gets going and gets established through out the whole fire basket then the temps will even out. The one side of the fire basket might have gotten more air so that side is hotter right away until all the fuel is lit. I don't use a chimney I use a torch or a charcoal iron. If I am using the torch I light it in four different spots on the basket to keep the heat even. And if I am using the iron I stick it right in the middle. This may not help you much but the key is to keep experimenting and don't get discouraged because once you use your UDS a bit you will love it and you will have no issues controlling temps and you will know pretty much where to sent your ball valve for what temps you want. Good luck. If you have any more issues let us know and we will help you figure it out.

post #3 of 18

what size is your exhaust? and twelve lit coals is a little high try lighting 8-10 its easier to get it hotter than to cool it down. and your temp gauge is not

gonna read true on the side like that.

post #4 of 18

Another thing you have to remember is ever time you open the lid (to add meat, spritz, etc.) you are going to spike your temps up because your fire basket is going to get lots of oxygen. So if you know you are going to open the lid do it quick and I also like to bring my temps down lower before I open it. For example if I am going to smoke at 225 I will bring my drum up to around 210 or so and get it stable at that temp because once I open my lid to add the meat the temps are going to spike up.

post #5 of 18

I never figured out why they use those nipples with caps and only one ball valve.  I use two ball valves and usually only need one. 


If you can find my post on first using a UDS you will see I had a heck of a time with my temps. Found out I lit too much coal at once.  I chased it from 200 to 300 and back until I got the hang of it .


Now I load my coal basket ( lump ) if I need to, and use 1 or 2 balls of newsaper on the side of the basket nearest my ball valves ( both my valves are on one side ).  Give it a bit to get goin put the lid on and monitor my Therm, once I hit 200 I shut one valve and close the other 1/2 way.  From that point I just make very small adjustment to keep it where I want it.


If you are indeed getting too much air from one nipple try replacing it with a ball valve or a reducer to a smaller nipple.  Then you can use a combination of inlets to get where you want to be.

post #6 of 18
Thread Starter 

Sorry...I should have posted a little more info...my bad....I am actually reading two different temps...an analog dial mounted on the side of the barrel...which read 190-200F the entire time. this is mounted about 1/2 inch below the cooking grate....then th temp I was chasing was on my PID controller.  this one is accurate to within one degree.  it is mounted just barely below the cooking rack on the opposite side of the analog.


I only removed the lid onve, to baste the drummies quick..otherwise I left it on the entire time.


I think you are right LugNutz....there just isn't enough control with one ball valve....I think I am going to replace one of the other pipe caps with another ball valve and see if that helps.  But yeah, otherwise I chased the temp from 210F to about 280F yesterday from about 2pm until 5pm.  Like I said,..if I put both pipe caps on and opened the ball valve full....it would drop down beloew 220F..and if I took one pipe cap off and close the ball valve 1/2 way it would heat up to 270F...these were readings all on the PID temp controller.


Oh yeah and my vent on the lid is 3 inch diameter, and it was fully open.



post #7 of 18

I found that most of my chasing was a result of too much adjusting the ball valve, mine seems to take very little to make a difference.  A lil patience will go a long way! 

post #8 of 18
Thread Starter 

so for say, ribs, or a brisket or pork butt...how much lump are you using in your firebasket?  Also, in the charcoal "starter chimney"...you just use 8-10 briquettes and light them...let them ash over..then add them to the UDS firewbasket in the middle of all the lump??



post #9 of 18

I fill my basket full and light it on one side only.  When I'm done smoking I just close all vents and next time I go out I still have plenty to cook with ( depending on what I'm cooking ).   I don't use a chimney, my basket kinda works like one.  I use news paper balled up and tucked under some of the lump and then light it up.

post #10 of 18
Thread Starter 

Lug..what are the dimensions of your firebasket?  Mine is fairly large..about 16 inches Diam..and 12 inches high.



post #11 of 18

about 14 dia and maybe 9-11 tall


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post #12 of 18
Originally Posted by flyweed View Post

I think you are right LugNutz....there just isn't enough control with one ball valve....




I would have to disagree with this. The idea is weather you have 3 or 4 inlets you will probably only need one whole ball valve to control you temps around 225. So lets say you have 4 inlets and one has a ball valve and the other three have caps. Once you get your temps up and you have put caps on the three you you are running with one ball valve. If you need less heat you back down to say 3/4 or 1/2 ball valve if you need more air you take a cap off and close up the ball valve which would give you the same as 1.25 or 1.5 ball valves. If you want to have two ball valves go right ahead but opening up one of the ball valves all the way and the other half is the same as having one of the caps removed and having your ball valve half open. Either way you look at it you are allowing the same amount of air into the barrel. Now if you are having issues with your cap being open and then the wind is blowing into the wide open cap well then you are going to get much more heat. I usually turn my barrel so the ball valve is turned away from the wind. I can control my temps very easy from 225-250 with one ball valve.

post #13 of 18
Thread Starter 

hmmm..interesting theory...It was quite windy the other day for my first smoke...so that could have been it..but my temps just went skyrocket when I had one cap off and couldn't do anything with the ball valve..and when I put the cap on....with the ball valve wide open, I was only hitting 220F max.


I got a couple fatties going on tomorrow...so am gonna fill the basket with lump (royal oak) and then add just 8 briqettes  to it that have been lit as the starter.



post #14 of 18

I only have one ball valve on mine 1/2". I also have a door which is pretty well sealed for the most part. I can keep mine at 250* without a problem. During the summer I keep the valve closed and during the winter I keep it open. I also use a water pan in mine.

post #15 of 18

It took me a burn or two to catch on to how my two different drums run. There is not a giant difference but there is a difference in mine.


Just a thought here, but if you have a pid control, can't you hook it to a stoker type fan? This could avoid all adjustments, maybe. I have never used one so I can only speculate.

post #16 of 18
Thread Starter 

Tom..thats exactly what I am going to be doing...I am waiting for my blower fan to get here yet from China..then it will be threaded to the ball valve..and connected to the PID..when the PID hits 225F..the fan will kick in and continue to 230F then shut off.  So it should work perfectly then I won't have to adjust anything. :)



post #17 of 18
Thread Starter 

hey guys..well I did a couple fatties last night on the UDS, and I controlled the temps much better, but still had to "mind the barrel" quite a bit....it still seems that if I closed two "capped" vents and left the ball valve open the temps still dropped too much (below 220F) and if I took one "cap" off of a vent hole and then used the ball valve for control, I could keep the temps around 250F.  I used a full basket of royal oak lump, and started it with newspaper on one side...put it in the UDS, and let the temps come up to 230F..before I started closing down vents.


Also..another question..are UDS's known to have hot and cold spots?  I have my PID mounted on the side of the barrel just under the cooking rack and it was reading about 223F when my Maverick on the opposite side was reading 252F..I know they are both accurate, as both test 212F in boiling water.  So after I pulled my fatties off...I put the two probes within about 2 inches of each other, except the PID probe was under the cooking grate and the maveriack was on top of the cooking grate.  the Maverick read 233F and the PID probe read 230F..so really really close in temp, but I didn't think the barrel would have such a wide temp gap from one side of the grate to the other.



post #18 of 18

Yea they can have hot and cold spots until the whole basket of fuel gets going evenly. I started lightning four or five spots on my basket so that the fire would start going evenly throughout my barrel. Or sticking a charcoal iron in the middle works good to but you have to wait a bit for the fire to get to the outside of the barrel so that the center and outside are roughly the same temps. Others may disagree but that is what I have found. If I just started one side of my basket I had troubles with temps between the two sides of the barrel. Also when I am doing a big cut of meat like a brisket or butt I usuall turn the meat 180 degrees around half way through the cook just to make sure it gets done evenly in the event that you have a bit of a hot/cold spot in the drum that day. I didn't flip my first brisket and the one end of the brisket got done faster than the other side.

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